Date: Tue, 23 Mar 2004 18:04:26 +0530
From: Dipankar Sarma <dipankar@in.ibm.com>
To: Andrea Arcangeli <andrea@suse.de>
Cc: tiwai@suse.de, Robert Love <rml@ximian.com>, Andrew Morton <akpm@osdl.org>,
       linux-kernel@vger.kernel.org
Subject: Re: [PATCH] RCU for low latency (experimental)
Message-ID: <20040323123426.GG3676@in.ibm.com>
Reply-To: dipankar@in.ibm.com
References: <20040323101755.GC3676@in.ibm.com> <20040323122925.GH22639@dualathlon.random>
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On Tue, Mar 23, 2004 at 01:29:25PM +0100, Andrea Arcangeli wrote:
> On Tue, Mar 23, 2004 at 03:47:55PM +0530, Dipankar Sarma wrote:
> > Here is the RCU patch for low scheduling latency Andrew was talking
> > about in the other thread. I had done some measurements with
> 
> I don't see why you're using an additional kernel thread. I told you one
> way to implement it via softirq taking advantage of the scheduler-friendy
> re-arming tasklets.

I have a patch for that too which I have been testing for DoS in
route cache, not latency. It is worth testing it here, however 
I think re-arming tasklets is not as friendly to latency as
executing the rcu callbacks from process context. One thing
I have noticed is that more softirqs worsen latency irrespective
of the worst-case softirq length.

Thanks
Dipankar
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